1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS ISO 8374:2001 ICS 37.0
2、40.99 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Photography Determination of ISO safelight conditionsThis British Standard, having been prepared under the direction of the Consumer Products and Services Sector and Policy Strategy Committee, was published under the author
3、ity of the Standards Policy and Strategy Committee and comes into effect on 7 September 2001 BSI 7 September 2001 ISBN 0 580 36010 5 BS ISO 8374:2001 Amendments issued since publication Amd. No. Date Comments National foreword This British Standard reproduces verbatim ISO 8374:2001 and implements it
4、 as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee CPW/42, Photography, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or p
5、roposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement in
6、ternational or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to i
7、nclude all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, th
8、e ISO title page, pages ii to v, a blank page, pages 1 to 13 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.Reference number ISO 8374:2001(E) INTERNATIONAL STANDARD ISO 8374 Second edition 2001-08-15 Photography Determination of ISO
9、safelight conditions Photographie Dtermination des conditions dclairage de scurit ISOISO 8374:2001(E) ii ISO 8374:2001(E)iii Contents Page 1 Scope 1 2 Normative references 1 3 Terms and definitions .1 4 Maintenance and recording of safelight conditions 3 5 Test methods3 5.1 Introduction3 5.2 Method
10、1 .4 5.3 Method 2 .6 6 Test method for safelight conditions during processing9 7 Evaluation.10 7.1 General10 7.2 Subjective (visual) procedure.10 7.3 Objective (instrumental) procedure.10 8 Designation 10 Annex A (normative) Safelight testing using a half-tone image 11 Bibliography13ISO 8374:2001(E)
11、 iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which
12、 a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all mat
13、ters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standa
14、rd requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Internationa
15、l Standard ISO 8374 was prepared by Technical Committee ISO/TC 42, Photography. This second edition cancels and replace the first edition (ISO 8374:1986), which has been technically revised. Annex A forms a normative part of this International Standard.ISO 8374:2001(E)v Introduction The term “safeli
16、ght” in photography is used to describe a light source that offers the user sufficient time to perform an operation without producing a detectable change in the photographic characteristics of a sensitized material. Because most sensitized materials are handled under safelight conditions by the manu
17、facturers or users, or both, it was considered desirable to specify a standard method to determine working conditions which are safe for sensitized materials. It is usually assumed, often incorrectly, that lighting conditions are safe if the density in a simple “fog test” is not changed by these con
18、ditions. This is untrue for many materials, particularly for black-and-white and colour papers, where an image area may be more sensitive than an unexposed area. Therefore, an unsafe lighting condition may go undetected if one looks for changes in unexposed areas only. Furthermore, the sensitivity o
19、f a sensitized product to a safelight may differ according to whether the safelight exposure is received before or after the practical exposure, and the magnitude or even the direction of this difference may in some cases vary from batch to batch of a given film or paper type. An additional consider
20、ation is the cumulative effect of successive exposures. Depending on the types of exposures and the emulsion formulation of the particular sensitized product, these exposures may be subadditive, additive or superadditive. Generally, the spectral quality for a safelight is selected as a compromise be
21、tween the visual response of a partially dark-adapted operator and the spectral response (of the product) to this light. This International Standard is not concerned with this selection. The object of this International Standard is to define when the exposure (the product of intensity and time) from
22、 a safelight has a detectable effect on the image-forming characteristics of a sensitized material. Since virtually all exposures are cumulative, exposure of a material to safelights should be kept to a minimum at all stages of handling (i.e., manufacturing, inspection, camera loading, splicing, pro
23、cessing, printing, etc.). This International Standard provides a means to isolate and evaluate any given single exposure to safelight irradiation among the several exposures likely to be incurred in the manufacturing and use cycle.INTERNATIONAL STANDARD ISO 8374:2001(E)1 Photography Determination of
24、 ISO safelight conditions 1 Scope This International Standard specifies the methods for determining the maximum exposure time that a given sensitized material can receive from a given safelight without affecting the quality of the final image. It also specifies the records which shall be maintained
25、for the components of a safelight and its operating environment. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, a
26、ny of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative docume
27、nt referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 5-2:2001, Photography Density measurements Part 2: Geometric conditions for transmission density. ISO 5-3:1995, Photography Density measurements Part 3: Spectral conditions. ISO 5-4:1995
28、, Photography Density measurements Part 4: Geometric conditions for reflection density. 3 Terms and definitions For the purposes of this International Standard, the following terms and definitions apply. 3.1 additivity condition wherein the effect of successive exposures received by a sensitized pro
29、duct produces a net photographic effect that is precisely that which would be predicted by a mathematical summation of the individual exposures 3.2 dot value apparent percentage of an area covered by half-tone dots which is calculated from the relative transmission densities of the area of dots, the
30、 solid area, and the area between dots 3.3 geometric mean the nth root of the product of n quantities, referring here to the square root of the product of two adjacent safelight exposure values 3.4 half-tone image image composed of dots at a given screen frequency (number of dots per centimetre) tha
31、t are varied in size (value) and shape to provide visual tonal gradationsISO 8374:2001(E) 2 3.5 hard dot half-tone dot with a sufficiently steep edge gradient such that the dot reproduces reliably in film duplication and in the production of a printing plate 3.6 ISO maximum safelight condition light
32、ing condition that provides half of that exposure which is the geometric mean between the exposure required to produce the smallest detectable change and the (adjacent) maximum exposure which gives no detectable change, evaluated by use of methods described in this International Standard 3.7 post-ex
33、posure latensification safelight exposure after a sensitized material receives a normal image-forming exposure 3.8 pre-exposure hypersensitization safelight exposure before a sensitized material receives a normal image-forming exposure 3.9 safelight combination of light source, filter and fixture yi
34、elding a specific spectral irradiance, appropriate for handling a particular sensitized material NOTE In some cases, the source itself may be spectrally correct without the need for a filter. 3.10 safelight filter spectrally selective absorbing material used with a specified light source to produce
35、the required safelight illumination 3.11 safelight fixture enclosure for a light source (such as tungsten) that dissipates heat and holds a safelight filter (if either are required) 3.12 safelight irradiance electromagnetic radiation emanating from a safelight that is incident on a sensitized materi
36、al NOTE A sensitized material generally has a spectral sensitivity very different from the human eye. This makes it possible for two safelights of differing spectral-power distributions to give the same “visual appearance” but affect a sensitized material quite differently. 3.13 safelight scale expo
37、sure exposure series using the safelight as the light source 3.14 safetime length of time that a sensitized product can be exposed to a safelight of a given intensity at a given distance NOTE This will be any time less than or equal to one-half of the geometric mean between the time required to prod
38、uce the smallest detectable change and the maximum time which gives no detectable change in a sensitized product, using the test conditions outlined in this International Standard.ISO 8374:2001(E)3 3.15 smallest detectable change smallest difference in the image density or hue that, for a given sens
39、itized product, can be seen in a side-by-side visual examination NOTE This can alternatively be measured by a densitometer if it has accuracy of density difference and repeatability better than or equal to either 0,005 or 0,5 % of the density, whichever is the greater. 3.16 stop term referring to a
40、factor of two change in exposure, or a change of approximately 0,3 log 10 exposure 3.17 subadditivity condition wherein the effect of successive exposures received by a sensitized product produces a net photographic effect that is less than that predicted by a mathematical summation of the individua
41、l exposures 3.18 superadditivity condition wherein the effect of successive exposures received by a sensitized product produces a net photographic effect that is more than that predicted by a mathematical summation of the individual exposures NOTE The phenomenon of superadditivity is demonstrated by
42、 most print materials. Method 1 determines at what density a given sensitized material is most sensitive to safelight exposure. In some cases, the material may be most sensitive over a range of densities from fog upwards; in such cases, a simple fog test would be adequate. 4 Maintenance and recordin
43、g of safelight conditions A record shall be made of all pertinent data including the safelight source type (e.g. light-emitting diode, electroluminescent panel, tungsten bulb, sodium vapour lamp, etc.), source wattage or milliamp draw, voltage, filter used (if any), approximate age of the filter, ty
44、pe and interior finish (e.g. white, matte black, silvered, etc.) of the safelight fixture, distance from the safelight to the sensitized material, exposure times and processing data. The data for indirect safelight illumination (aimed at walls or ceilings) shall also include the colour and reflectan
45、ce of the surfaces and appropriate geometrical descriptions. Once established, the safelight exposure variable shall be maintained by ensuring that proper replacement lamps are used, that filters are not fading, that the distance from the safelight to the sensitized material is maintained, and that
46、the environment has not changed (by painting walls, etc.). Any changes to the elements described above shall be evaluated individually via methods set forth in this International Standard. 5 Test methods 5.1 Introduction This clause describes two methods of testing to determine the maximum safelight
47、 condition. Method 1 (see 5.2): the most general method and the one that shall be used when the safelight/material relationship is unknown. It makes no assumptions regarding a) the image density at which safelight exposure produces the maximum effect, and b) the order of exposures (safelight and ima
48、ge) that produces the maximum effect.ISO 8374:2001(E) 4 Method 2 (see 5.3): intended for use only when the basic relationship between safelight and sensitized material is already known. It is thus useful for in situ testing of safelit areas, once Method 1 has yielded the safelight/material relations
49、hip. (Method 1 may also be used for in situ testing, but it is more cumbersome than Method 2.) In Method 2, the image exposure is simulated by a uniform exposure that produces the greatest sensitivity to subsequent safelight exposure. (In some cases, the material may be most sensitive over a range of densities from fog upwards; here, Method 2 can be reduced to a simple fog test.) The description in 5.3 includes testing both orders of exposures (safelight then image, and image then safelight); but if the order producing the greatest safelight sensitivity is known,
